In order to transition to a low carbon economy, we need to examine every stage of the delivery and utilization of power, so we can optimise it, where possible. Insufficient attention has been paid to variable speed electric motors in business, industry and occasionally residential applications. Reducing loads also reduces consumer costs.
In the UK it is estimated that electric motor and drive systems account for over 60 percent of industrial electricity demand. This usage is from fans, pumps, compressors for air and refrigeration, and HVAC.
Some loads will be fixed, and there the option is to have an efficient, fixed speed drive system. However many loads can be varied or modulated, and here the opportunity is for a variable speed system to save energy.
Using Variable Speed Drives (VSDs) to control suitable motor systems can often save 15-40% of power used. This is particularly noticeable in fan and pump applications, where a mechanical system can be replaced and the system run at optimum efficiency for the task required of it.
CEMEP (the European Committee of Manufacturers of Electrical Machines and Power Electronics) believes that global electricity consumption could be reduced by eight percent if VSDs were used in every applicable circumstance.
The options for variable speed motors are:
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DC Motors: this is the traditional option for variable speed applications, but can have maintenance issues
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AC variable speed motors: often used for smaller applications, like fan coil or condensing units
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AC Motors and VSDs: this is the best solution for energy saving and HVAC applications
As regulations tighten, and everyone on the power supply chain has to do their bit to contribute to net zero, replacing older systems with VSDs is an option that will have benefits in load management, and therefore emissions and costs reductions.